VAX Floating Point Numbers

Note that some VAX models as purchased may not implement some of the formats
shown below. The bits are normalized such that there is one "hidden"
bit to the left of the Most Significant Bit (MSB) of the Fraction.
For instance, that results in 24 bits of Fraction for the F_Floating point
shown below.

The exponent is "Excess 128"; that is, the binary value of these 8 bits
must be subtracted by 128 (decimal) to obtain the actual exponent.

For the 32 bits or 8 bytes shown below, the lowest addressed byte is bits
0-7; the next, bits 8-15; and so on.

F_floating point numbers have the range of approximately
plus or minus 2.9E-39 to plus or minus 1.7E+38, with a precision of approximately
seven decimal digits.

G_floating point numbers have the range of approximately
plus or minus 5.6E-309 to plus or minus 0.9E+308, with a precision of approximately
15 decimal digits. The exponent has a bias of 1024 (not 128).

H_floating point numbers have the range of approximately
plus or minus 8.4E-4933 to plus or minus 5.9E+4931, with a precision of approximately
33 decimal digits. The exponent has a bias of 16384 (not 1024).